The long term goal of the proposed project is to start a comprehensive research program investigating the brain's attentional control mechanisms. This will entail the use of multi-modal neuroimaging techniques, in particular the event-elated potential (ERP) and functional Magnetic Resonance Imaging (fMRI) methods. It is expected that the combined use of these techniques will eventually provide pictures of the spatiotemporal dynamics of brain activity that either method alone could not provide. The specific goal for the project proposed here represents an attempt to contribute to the understanding of the cognitive and neural mechanisms for the generation and control of actions. It is hypothesized that facilitation effects in response selection tasks, rather than being viewed as mirror images of response interference effects, can best be explained in terms of the contribution of a fast and stimulus-driven pathway, that operates outside of volitional control, to behavior. Two event-related fMRI studies are proposed to delineate the neural basis for this pathway with appropriate task manipulations.